Drive train for rotary floor conditioners

ABSTRACT

A WORKHEAD ASSEMBLY FOR A FLOOR CONDITIONER HAVING A GEAR TRAIN WHICH INCLUDES BEVEL GEARS. MEANS ARE PROVIDED TO INSURE PROPER MESHING OF CERTAIN GEARS NOTWITHSTANDING ADDITIVE MANUFACTURING TOLERANCES BETWEEN COOPERATING PARTS WHILE OBVIATING SELECTIVE ASSEMBLY TECHNIQUES OR ABNORMALLY CLOSE MANUFACTURING TOLERANCES.

Jan. 12, 1971 c. A. LUCKNER, JR 3,554,043

Q IJRIVE TRAIN FOR ROTARY moon counxw'xoumas 4 Sheets-Sheet 1 Filed June 2,-1 969 Jan. 12, 1971 c. A. LUCKNER, JR

DRIVE TRAIN FOR ROTARY FLOOR CONDITIONERS Filed June" a. 1969 4 Sheets-Sheet 2 Filed June 2, 9

DRIVE TRAIN FOR ROTARY FLOOR CONDITIONERS 4 Sheets-Sheet 3 12, 1971 c. A. LUCKNERHJR 3,554,043

1mm. TRAIN FOR ROTARY FLOOR counz'rzonmns Filed June 2, 1969 4 Sheets-Sheet 4 United States Patent 3,554,043 DRIVE TRAIN FOR ROTARY FLOOR CONDITIONERS Clark A. Luckner, Jr., North Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a corporation of Delaware Filed June 2, 1969, Ser. No. 829,661 Int. Cl. F16h 1/12,55/18 US. Cl. 74-409 Claims ABSTRACT OF THE DISCLOSURE A workhead assembly for a floor conditioner having a gear train which includes bevel gears. Means are provided to insure proper meshing of certain gears notwithstanding additive manufacturing tolerances between cooperating parts while obviating selective assembly techniques or abnormally close manufacturing tolerances.

BACKGROUND OF THE INVENTION Field of the invention Description of the prior art The Hoover Company manufactures an ambulatory machine, generally known as FLOOR-A-MATIC which can be used for scrubbing wet floors and which also removes the ditry water from the floor after the scrubbing operation. An early version of this machine is the Model 3600. All FLOOR-A-MATIC machines have a workhead assembly generally consisting of a workhead body subassembly and a drive subassembly. The drive subassembly comprises an integral motor-pump unit generally described in the earlier Case 1778 titled Motor Pump Shaft Seal by Howard L. Allen and Charles D. De- Gratf and Case 1789 titled Motor Pump Housing by Robert F. Dyer.

In the earlier 3600 machine the armature of the motorpump has a first worm gear formed in the outer end of its shaft which was supposed to be in proper mesh with a second worm gear of a driven wheel mounted on a horizontal axis on an ear of the workhead body subassembly when the motor pump housing was mounted on the upper face of theworkhead body subassembly. A first bevel gear was formed integrally with the second worm gear on the driven wheel and was in mesh with a second bevel gear of a transfer wheel mounted on a vertical axis on the top surface of the workhead body subassembly. A spur pinion was formed integrally with the second bevel gear on the transfer wheel and meshed with the next gear in line in the gear train designed to simultaneously drive a pair of parallel brush drive shafts. During the mounting of the drive subassembly on the workhead body subassembly, it was found that the manufacturing tolerance of the various elements could not be held close enough, in mass production, to obtain a satisfactory meshing of the pair of worm gears. To overcome this, a selective assembly technique was utilized. The spacing between the mounting surface of the motorpump housing and the axis of the first worm gear was Patented Jan. 12, 1971 measured and the drive subassemblies were divided into five groups depending on the spacing. The spacing of the axis of the driven Wheel, from the upper mounting surface of the workhead body subassembly, was also measured and the subassemblies were also divided into -five groups depending upon the spacing. The respective groups of the drive subassemblies and the groups of the workhead body subassemblies were matched to obtain satisfactory meshing between the first and second worm gears. However, a selective assembly technique, such as described above, utilized in a production line, is a costly operation which is to be avoided if possible.

SUMMARY OF THE INVENTION A workhead assembly comprises a drive subassembly and a workhead body subassembly. The drive subassembly has a rotary motor mounted on a support member or housing. A first portion of a constant-mesh gear train, between the motor on the drive subassembly and a driven member on the workhead body subassembly, is mounted in the drive assembly including a driven wheel having a bevel gear designed to mesh with a bevel gear of a transfer wheel journalled on the upper face of the workhead body subassembly on which the drive subassembly is mounted. One of the bevel gears is mounted on the respective subassembly so that it is adjustable in the axial direction and is spring biased toward the bevel gear of the other subassembly, whereby satisfactory meshing of the first and second bevel gears can be obtained without selective assembly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a FLOOR-A- MATIC machine within which a workhead assembly is mounted.

FIG. 2 is a perspective exploded view of the workhead subassembly of the prior model of the FLOOR-A-MATIC machine.

FIG. 3 is an exploded perspective view of the newly designed workhead assembly of the present version of the FLOOR-A-MATIC machine, incorporating the present invention.

FIG. 4 is a bottom view of the motor pum-p housing of the workhead assembly of the present version of the FLOOR-A-MATIC machine.

FIG. 5 is a top plan view of the workhead assembly of the present version of the FLOOR-A-MATIC machine with portions broken away to better illustrate the invention.

FIG. 6 is a sectional view of the present workhead assembly taken through lines 6-6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, in FIG. 1 is illustrated a FLOOR-A-MATIC floor conditioner generally designated 10 having a workhead assembly 12, partially hidden by a decorative outer shell 14, having a suction nozzle 15 and a pair of parallel axled rotary brushes 16 (only one shown in this view) extending from the lower end thereof.

In FIG. 2 the workhead assembly 12 of the prior model is illustrated. In this figure it can be seen that the motor-pump housing 18, having an electric motor 20 therein, comprises a drive subassembly generally designated 22 which is mounted on a workhead body subassembly, generally designated 24'. The housing 18' of drive subassembly 22' has a mounting flange 26 around the lower end thereof with a plurality of spaced mounting holes 28 formed therein.

The mounting surfaces of the workhead body subassembly 24 has a plurality of upstanding bosses 30- having tapped mounting holes 32 extending axially therethrough whereby the subassemblies may be fixedly bolted together. The motor in the motor-pump housing 18 has a rotatable armature, drive shaft 34, with a driving gear, a first worm gear 36, formed on the outer end thereof. The worm gear 36 is designed to be in constant mesh with a worm gear 38 of a driven wheel 40. The second worm gear 38 is mounted on a horizontal stub axle 41, parallel to the drive shaft 34, fixed at one end in an integral vertical ear 42 upstanding from the upper mounting surface of the workhead body subassembly 24'.

A first bevel gear 44 is formed coaxially and integrally as part of the driven wheel and is in constant mesh with a second bevel gear 46 mounted on a transfer wheel 48' which is journalled on a vertical stub axle 68 fixed in the upper face of the workhead body subassembly 24'. A spur pinion 50', formed integrally and coaxially on the transfer wheel 48, is in mesh with a parallel axled first spur idler gear 52. The spur idler gear 52 is in constant mesh with a second spur idler gear 54 and a first brush driving gear 56 fixed on a first brush driving shaft journalled through the workhead body. The second spur idler gear 54 is also in constant mesh with a second axled brush driving gear 58 fixed on a second brush driving shaft 62 journalled through the workhead body. When the drive subassembly 22' is mounted on the workhead body subassembly 24', the motor 20 drives brush shafts 60 and 62 in opposing directions through the gear train.

To provide for a variation in the meshing of the gears in the drive and workhead body subassemblies without using selective assembly techniques, the workhead assembly has been redesigned, as shown in FIGS. 3 through 6. The driven wheel 40, identical with the driven wheel of the earlier model, has been moved from a mounting position on the workhead subassembly 24 to a mounting position on the drive subassembly 22. With the driven wheel 40 journalled in the housing 18 there is no problem in holding tolerances between the armature shaft 34 and a mounting shaft 64 upon which the driven wheel 40 is now journalled. The tolerances problem, during assembly, has been shifted to the meshing of the first bevel gear 44, on the driven wheel 40, and the second bevel gear 46 on a revised transfer wheel 48.

The driven wheel 40 is located in a separate cavity 66 (FIGS. 3 and 6) just ahead of motor chamber 69. The driven wheel 40 is molded on a bronze bushing 70 which is designed to rotate on the non-rotatable mounting shaft 64. The shaft 64 is inserted through snugly fitted bore 72 in the outer wall of the housing 18 and has a reduced diameter inner end 74 which fits snugly into a small bore 1 76. The outer end of the bushing 70 rides against an L- shaped thrust plate 78 trapped on the shaft 64 between the outer wall 80 of the housing 18 and end of the bushing 70. The foot 82 of the L overlies an undercut portion 84 at the lower end of the wall 80 to prevent rotation of the thrust plate 78. A second L-shaped thrust plate 86 is trapped on the reduced diameter inner end 74 of the shaft 64 between the inner wall 88 of the cavity 66 and the outer end of the large diameter main portion of the shaft 64. The foot 90 of the thrust plate 86 underlies the edge of the bottom wall 92 of the motor chamber 69 to prevent rotation of the thrust plate 86. A sheet metal retainer 94 (illustrated most clearly in FIG. 3) locks the shaft 64 against axial movement and rotation. The retainer has a pair of spaced legs 96 which extend across a circumferential groove 98 in the outer end of the shaft 64 which, when the elements are assembled, is located between the outer wall 80 of the cavity 66 and the thrust plate 78. A depending tab 99 of the retainer 94, centrally located between the legs 96 fits into an axial groove 100 which intersects the circumferential groove 98. The axial groove is relatively deep with respect to the circumferential groove 98. An upper tab 102 of the retainer 94 is located adjacent a cutout 104 in the upper end of the outer wall 80 of the cavity 66 so that the retainer can be easily handled. The aforementioned structure permits the driven wheel 40 to rotate with minimal friction while preventing relative motion between the metal shaft and the walls of the housing 18, which is preferably made of plastic.

The transfer wheel 48, as shown in FIG. 6, has an axial passage 106 through which a stub axle 68, fixed in the upper mounting face of the workhead body subassembly 24, extends. The lower portion of the transfer wheel 48 is counter-bored at 108 to accept a compression spring 110 trapped between the upper end of the counter-bore 108 and a mounting boss 112 formed on the upper mounting surface of the workhead body subassembly 24 coaxially with the stub axle 68. With this arrangement the transfer wheel 48 is spring biased upwardly to yieldably press the bevel gear 46 into satisfactory meshing engagement with the bevel gear 44 of the driven wheel 40. Therefore, within manufacturing tolerances, the meshing of the bevel gears, mounted in the two subassemblies, is self adjusting.

The teeth of the spur pinion 50 of the revised transfer wheel 48 are wider than the teeth on the first idler gear 52 so that the teeth on the first idler gear 52 are always in mesh, over their entire widths, with the teeth of the spur pinion 50. As discussed with respect to FIG. 2, the first idler gear 52 is in constant mesh with the first brush driving gear 56 which is fixed on the brush driving shaft 60. The first idler gear 52 is also in mesh with a second idler gear 54 which in turn is in mesh with a second brush drive gear 58, fixed on the brush driving shaft 62. The brush driving shafts 60 and 62 are designed for removably mounting the driven brushes 16 located beneath the workhead assembly (FIGS. 5 and 6). The meshing gears 50, 52, 54, 56 and 58 are preferably located in a single plane on the upper surface of the workhead body subassembly 24 to simplify the construction.

In FIG. 4 the lower mounting face of the motor-pump housing 18 of the drive subassembly 22 is shown. The lower face of the housing 18 is designed so that the gears mounted on the workhead body subassembly 24 are enclosed thereby. Furthermore, the transfer wheel 48 and the idler gears 52 and 54 are merely slidably received on their stub axles and are axially restrained by means of locating bores 114, 116 and 118, respectively, formed in the under surface of the housing 18.

The bores 116 and 118 are substantially larger than the stub axles fitting therein so as to allow a certain amount of leeway in putting together the workhead assembly 12. The stub axle 68, upon which the transfer wheel 48 is mounted, is a reasonably tight fit in the bore 114 whereby the axles 64 of the driven wheels 40 and 68 of the transfer wheel 48 are held normal with respect to each other. The interfitting of the gear stub axles, fixed in the upper surface of the workhead subassembly 24, with the bores in the bottom surface of the housing 18 of the drive subassembly 22, can best be seen in FIG. 6.

What is claimed is:

1. A workhead assembly comprising:

(a) a drive subassembly including:

(1) a support member,

(2) motor means including a rotating drive shaft journalled in said support member,

(3) driven wheel means mounted in said support means,

(4) means for drivingly connecting said drive shaft with said driven wheel means,

(5) a first bevel gear on said driven wheel means;

(b) a workhead body subassembly including:

(1) a mounting surface,

(2) transfer wheel means journalled on said mounting surface,

(3) a second bevel gear formed on said transfer wheel means on an axis normal to the axis of said first bevel gear on said driven wheel means,

(4) and gear means for drivingly connecting said transfer wheel with at least one axially displaced parallel rotatable shaft, and

() means for yieldingly biasing one of said wheel means along its axis to urge the bevel gear integral therewith into a proper meshing relationship with the bevel gear of the other of said wheel means.

2. The workhead assembly of claim 1 wherein said means for yieldingly biasing said one of said wheel means comprises a stub axle mounted in the respective subassembly, a coaxial circular aperture through said one of said wheel means through which the stub axle extends for rotatably mounting said one of said wheel means, said circular aperture being counter-bored along a portion of its length, said counter-bore opening adjacent the mounting surface of said respective subassembly, and compression spring means mounted between the mounting surface of said respective subassembly and the inner end of said counter-bore.

3. The workhead subassembly of claim 1 wherein in addition to said second bevel gear said transfer wheel means comprises a spur pinion in mesh with an axially spaced spur gear, said teeth of said spur pinion being wider than said teeth on said spaced spur gear with which it meshes, whereby the teeth of said spur pinion are in contact over the entire width of the teeth of said spaced spur gear over the range of manufacturing tolerances allowable between the drive and workhead body subassemblies.

4. The workhead subassembly of claim 1, wherein means are provided for positively locating said axes of said transfer wheel means and'said driven wheel means with respect to each other.

5. The workhead subassembly as recited in claim 4, wherein said means for locating said axis of said transfer wheel means with respect to the axis of said driven wheel means comprises a stub axle upon which said transfer wheel means is mounted, said stub axle extending completely through said transfer wheel means, a bore extending into the mounting surface of said drive subassembly into which said stub axle extends for positively locating the axis of said transfer wheel means with respect to the axis of said driven wheel means.

6. The workhead assembly of claim 1, wherein said driven wheel means is rotatably journalled in said drive subassembly on an axis substantially parallel to and displaced from the axis of said drive shaft.

7. The workhead assembly of claim 6, wherein there is worm gear means on said drive shaft and a meshing worm gear integral with said driven wheel means.

8. The workhead assembly of claim 6, wherein said motor means is located in a chamber in said support member, an integral cavity at one end of said support means adjacent an end of said motor means, said rotating drive shaft extending into said cavity, said driven wheel means being located in said cavity and rotatable on an axle having its opposite ends supported in bores in opposing walls of said cavity parallel to said drive shaft.

9. The workhead assembly of claim 8, wherein a removable plate retainer means coacts with said axle to prevent axial movement or rotation of said axle with respect to said support means.

10. The workhead assembly of claim 1, wherein said one of said wheel means that is yieldably biased is said transfer wheel means journalled on said mounting surfaces of said workhead body subassembly.

References Cited UNITED STATES PATENTS 3,449,976 6/1969 Fergason.

LEONARD H. GERIN, Primary Examiner US. Cl. X.R. 7442l 

